I.— A MONOGRAPH OF THE TERRESTRIAL PALAEO- 

 ZOIC ARACHNIDA OF NORTH AMERICA 



By ALEXANDER PETRUNKEVITCH, Ph.D. 



Assistant Professor of Zoology, Yale University, New Haven, Connecticut. 



INTRODUCTION 



While European Carboniferous Arachnida have been made the 

 subject of careful study, the results of which are incorporated in 

 two extensive monographs, one by Fritsch in 1904 and the other by 

 Pocock in 191 1, the North American forms have received little atten- 

 tion since the publication of Saidder's researches. It is true that a 

 few new forms have been described recently, but no attempt has been 

 made to reinvestigate the whole subject. Moreover, as an extensive 

 kno\\' ledge of Arachnology and especially of the external morphology of 

 arachnids, is imperative for a correct interpretation of fossil remains, 

 there is nothing surprising in the fact that errors crept into the 

 diagnoses of Scudder and that these were repeated by Melander. 

 Another reason for such errors Was the fact that Scudder' s and Melan- 

 der's specimens were not sufficiently cleaned of the white ^ mineral 

 which often entirely concealed the important characters. We find 

 the most striking examples of this in an unpublished specimen belong- 

 ing to the U. S. National Museum, which has been identified by 

 Scudder as Graeophonus carbonarius, while it is in fact a new species 

 of Anthracomartus , and in Kustarachne sulcata of Melander which 

 is a typical Curculioides. Naturally the diagnoses of the genera 

 themselves have likewise suffered from incomplete knowledge of the 

 type specimens. This is rather unfortunate, since it not only neces- 

 sitates a shifting of the American species from one genus to another, 

 but resulted also in a Wrong application of some generic names for 

 European species, an unavoidable error on the part of the European 

 investigators Who did not have an opportunity to examine the Ameri- 



^ In some specimens it is calcium carbonate mixed with iron carbonate, 

 n others kaolin. 



